“The U.S. Geological Survey Water Resources Mission Area (WMA) is planning to intensively study ten Integrated Water Science (IWS) basins throughout the United States over the coming decade, integrating monitoring, research, modeling, and assessment to improve understanding of water availability in a wide range of environmental, hydrologic, and landscape settings. Each IWS basin will be representative of a larger region, and high-density monitoring and cutting-edge research will be used to better understand and model factors affecting water availability (quantity, quality, and use) in the basin, the larger region, and nationally. The first two IWS basins have been selected to be in the Delaware River basin and Upper Colorado River basin and the Illinois River basin has been selected to be the 3rd IWS basin. IWS activities will be accomplished primarily through three WMA programs—the Next Generation Water Observing System (NGWOS) program, Integrated Water Availability Assessments (IWAAs) program, and the Integrated Water Prediction (IWP) program. The three primary programs will be supported by up to eleven other WMA programs that will provide additional monitoring, research, and information dissemination support on an as needed basis, driven by the issues in each IWS basin.

The USGS WMA has recently completed its planned process for selection of a 3rd IWS Basin (formerly referred to as NGWOS Basins). The selection process included the following steps:

1. 1. Establishment of the target region (Midwest) and science issues (nutrient delivery and harmful algal bloom (HABs)) by the WMA Leadership,
   2. Prioritization of candidate basins in the target regionsusing a quantitative ranking scheme (Van Metre et al, 2020) combined with quantitative estimates for nutrient delivery and HABs occurrence,
   3. Gathering of input from USGS Regional offices and local USGS Science Centers, and
   4. Engagement with targeted national and regional stakeholders in the region to understand science and monitoring gaps and priorities, as well as upcoming initiatives in the candidate basins.

Based on the above factors, the Illinois River Basin was selected as the 3^rd IWS Basin.

The Illinois River Basin provides an excellent opportunity to integrate monitoring, research, modeling, and assessment in ways that will enable the USGS to better understand water availability in a Midwestern basin and extend that understanding to the larger region. The Illinois River Basin consists of extensive urban and agricultural land uses that can help improve understanding of how nutrient sources, in combination with climate and land-use change, may limit water availability. HABs occurrences are commonplace in the Illinois River Basin, and the basin is estimated to be one of the largest geographic sources of nutrients to the Gulf of Mexico. Insights gained through IWS basin activities in this area will not only inform nutrient reduction efforts and further understanding of the factors leading to HABs occurrences in Illinois, but also in the broader Mississippi River Basin and Midwestern US. These insights can ultimately help to optimize nutrient management, reduce nutrient loads to the Gulf of Mexico and Great Lakes, and evaluate how conservation practices may ameliorate water-quality trends at various spatial scales.  Finally, the Illinois River Basin provides many opportunities for integration among water, ecosystem, hazards, and environmental health activities within the USGS, while also providing direct linkages and leveraging opportunities with our Federal, State, local, and non-governmental partners.

It is important to note, that proceeding with these planned IWS activities in each new basin is dependent upon appropriations. Over the course of 2021, USGS WMA will begin broad internal and external stakeholder engagement to help develop a science and monitoring plan for the Illinois River Basin, a plan that will guide USGS IWS activities in the basin over the coming years, dependent upon appropriations. More details will be forthcoming, particularly on upcoming stakeholder engagement opportunities. Should you have any questions in the meantime, please contact Chad Wagner (cwagner@usgs.gov) or your local USGS Science Center representative.”

– Adrienne Bartlewitz on behalf of Donald Cline.